1. Field of the Invention
The present invention relates to an electron emitting device, an electron source, and an image forming apparatus.
2. Related Background Art
Conventionally, two types of electron sources (cathodes), that is, a thermionic and a cold cathode have been known as the electron emitting device. As the cold cathode, there are a field emission type (hereinafter referred to as an FE type) electron emitting device, a metal/insulating-layer/metal type (hereinafter referred to as an MIM type) electron emitting device, a surface conduction type electron emitting device, or the like.
As examples of the FE type, those disclosed in W. P. Dyke & W. W. Dolan, “Field Emission”, Advance in Electron Physics, 8, 89 (1956), C. A. Spindt, “Physical Properties of thin-film field emission cathodes with molybdenum cones”, J. Appl. Phys., 47, 5248 (1976), and the like have been known.
As examples of the MIM type, the one as disclosed in C. A. Mead, “Operation of Tunnel-Emission Devices”, J. Appl. Phys., 32, 646 (1961), and the like have been known.
Also, as recent examples, Toshiaki Kusunoki, “Fluctuation-free electron emission from non-formed metal-insulator-metal (MIM) cathodes fabricated by low current anodic oxidation”, Jpn. J. Appl. Phys. Vol. 32 (1993) pp. L1695, Mutsumi Suzuki, et.al, “An MIM-cathode array for cathode luminescent displays”, IDW'96, (1996) pp. 529, and the like have been studied.
As examples of the surface conduction type, there are the ones as described in Elinson's report (M. I. Elinson, Radio Eng. Electron Phys., 10 (1965)), and the like. This surface conduction type electron emitting device is realized by utilizing the phenomenon that electrons are emitted out of a small area thin film formed on a substrate when a current is made to flow in parallel with the film surface. As the surface conduction type electron emitting device, the device using an SnO2 thin film described in the above Elinson's report, a device using an Au thin film (G. Dittmer. Thin Solid Films, 9, 317 (1972)), a device using an In2O3/SnO2 thin film (M. Hartwell and C. G. Fonstad: IEEE Trans. ED Conf., 519 (1983)), and the like, have been reported.